Those skilled in the art know that an alternative compressor comprises means to move at least a movable assembly, wherein at least a piston is capable of being reciprocating displaced in the axial direction inside a cylinder in order to effect compression on working fluid.
The present state of the art comprises some models of alternative compressor assembly, such as, for example, linear compressor.
A linear compressor has its movable assembly driven by a linear-type electric engine, wherein a portion of said engine is static (normally secured to a compressor cylinder) and at least a portion is dynamic (normally capable of linear movement and coupled to said movable assembly of the compressor). In this context, the movable assembly of the compressor follows an axial and reciprocating displacement of the dynamic portion of the engine to cause compression on a working fluid.
According to the present state of the art, a movable assembly of alternative compressor comprises at least a piston and a connecting road, which includes a body responsible for connection between said engine and piston. Constructions are known where one of the connecting road ends is directly associated with the shaft/dynamic portion of the engine (the other end being associated with the piston). Constructions where one of the connecting rod ends is associated with a series of additional elements which are in turn associated with the shaft/dynamic portion of the engine (the other end being associated with the piston) are also known.
With regard to association of one of the connecting rod ends with the piston, also known are several constructions wherein the simplest construction comprises a direct fixation between a connecting rod and a piston.
The present state of the art also provides for intermediate elements used between an association of a connecting rod and a piston.
An example of using intermediate elements for association of a connecting rod with a piston is described in U.S. Pat. No. 3,263,311. Said US Patent describes an association between a piston in a connecting rod wherein said piston is essentially hollow and receives in its interior a connection insertion which in turn receives a connecting rod end. Said connection insertion is fixed inside the piston through a stop also previously formed inside the piston.
The large drawback of this example of construction resides in the fact that the connection insertion is fixed inside the piston through inner stops (inner grooves) physically existing in the piston itself. That is, in addition to the fact that said stops do not comprise an efficient fixation means, they also cause an increase in the piston manufacture complexity and costs.
Another example of a similar construction is disclosed in U.S. Pat. No. 3,473,444, which refers to a connecting rod/piston arrangement consisting of a hollow piston and a connecting rod having a swivel end. In this case, the piston comprises a contacting insertion housed in its interior, said insertion being formed by two different parts which are assembled under especial processing conditions. Said insertion is especially suitable for receiving swivel end of the connecting rod.
The large drawback relative to this constructional example resides in the fact that said insertion, assembled inside the piston, fulfills all the internal volume thereof, wherein reduction in the piston mass is not possible. Moreover, said insertion is securely associated only with the piston interior while said connecting rod comprises several degrees of freedom of movement when coupling to the insertion. This is not suitable for some specific applications.
Another example of similar construction is described in U.S. Pat. No. 4,831,916, which refers, among other elements, to a rigid piston comprising a connection opening and an insertion member housed in said connection opening of the piston. In this case, a connecting road functionally connected to said insertion member, and, therefore, associated with the piston is disclosed. Said connecting rod is kept inside the insertion member through resilient portions disposed at the insertion member itself.
A large drawback concerning this example of construction resides in the fact that said insertion, in addition to being secured to the piston end (being capable of being moved away) fixes said connecting through resilient portions, which may undergo deformation and break
In view of the foregoing, it can be obviously observed that there is a need for developing a solution free of the disadvantageous aspects mentioned above.